Slurry Composition for Final Polishing of Silicon Wafers and Method for Final Polishing of Silicon Wafers Using the Same

a technology of silicon wafers and slurry compositions, applied in the direction of lapping machines, grinding devices, other chemical processes, etc., can solve the problems of lpds, haze and microroughness other than the increase of the polishing rate, and suggest improved performance in terms of light point defects (lpds), so as to reduce the number of lls defects, improve the yield of processes, and reduce the microroughness or haze

Inactive Publication Date: 2008-06-05
CHEIL IND INC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0017]The present invention can provide an optimum slurry composition that uses abrasive particles having an optimum particle diameter to reduce the microroughness or haze (which is a result of diffuse reflection of light by fine particle clusters) of polished wafer surfaces and to reduce the number of LLS defects having a size larger than about 50 nm, which is the next standard specification issued in the semiconductor manufacturing industry, thereby improving the yield of processes for polishing silicon wafers.

Problems solved by technology

However, these polishing slurry compositions lie within the general ranges, and particularly do not suggest improved performance in terms of light point defects (LPDs), haze and microroughness other than increased polishing rate.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

example 1

[0059]Colloidal silica particles having a primary particle diameter of 20 nm are diluted in deionized water up to 5% by weight of the silica particles, and then 0.5% by weight of ammonia is added thereto to adjust the pH value to 10.8. 0.5% by weight of hydroxypropylcellulose having a weight average molecular weight of 400,000 is used as a water-soluble thickener. As indicated in Table 1, to the mixture are added 0.002% by weight of the acetylene glycol and 0.2% by weight of piperazine as a heterocyclic amine to prepare a slurry composition.

[0060]The slurry composition is diluted 40-fold with deionized water and used for polishing of silicon wafers. The diluted slurry is used to polish a p-type 200-mm flat wafer with a (100) orientation using a polisher (UNIPLA 211) to which a hard urethane polishing pad is attached. Thirty wafers are polished per slurry sample and the surfaces of the wafers are analyzed using a SURFSCAN SP-1 (KLA-TENCOR).

example 2

[0061]A slurry composition is prepared in the same manner as in Example 1, except that ethylpiperazine is used instead of piperazine. The polishing performance of the slurry composition is evaluated by the same procedure as described in Example 1.

example 3

[0062]A slurry composition is prepared in the same manner as in Example 1, except that aminoethylpiperazine is used instead of piperazine. The polishing performance of the slurry composition is evaluated by the same procedure as described in Example 1.

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Abstract

Disclosed is a slurry composition for final polishing of silicon wafers to achieve mirror surfaces of the wafers. The slurry composition can include deionized water, abrasive particles, a pH-adjusting agent, a water-soluble thickener, an acetylene surfactant, and a heterocyclic amine. The particle diameter of the abrasive particles and the contents of the components can be selected so that the slurry composition can markedly reduce the number of LLS defects having a size larger than about 50 nm formed on the surface of wafers, and greatly reduce the haze and microroughness of wafer surfaces.

Description

FIELD OF THE INVENTION[0001]The present invention relates to a slurry composition useful in final polishing of silicon wafers. More specifically, the present invention relates to a slurry composition for final polishing of silicon wafers that can reduce the microroughness or haze (which is a result of diffuse reflection of light by fine particle clusters) of polished wafer surfaces, as well as reduce the number of localized light scattering (LLS) defects having a size larger than about 50 nm formed on the surface of silicon wafers.BACKGROUND OF THE INVENTION[0002]Chemical mechanical polishing (CMP), which is a final process for the production of silicon wafers, is performed to remove physical surface defects, such as microscratches, and to reduce the surface microroughness of silicon wafers, thus making the surface of the wafers soft. Wafers having undergone the CMP process can have mirror surfaces with few defects. In recent years, regulations to restrict the size of localized ligh...

Claims

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Application Information

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Patent Type & Authority Applications(United States)
IPC IPC(8): C09K3/14B24B37/00H01L21/304
CPCC09K3/1463C09K3/1409H01L21/304
Inventor ROH, HYUN SOOLEE, IN KYUNG
Owner CHEIL IND INC
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